Denmark's plan to cull 17 million mink after a mutated coronavirus strain was found is in doubt after the government learned it did not have the legal authority to carry out the operation.
Authorities started the cull last week, but discovered the measure does not have enough support in parliament.
On Tuesday, the minority Social Democratic government put forward new legislation for a cull, but the opposition said it will not let the draft bypass the usual 30-day legislative process.
The Covid-19 strain found in Danish mink has the ability to jump species, from animal to people, and could reduce the effectiveness of a vaccine.
With Prime Minister Mette Frederiksen lacking the three-quarters majority needed to pass such emergency legislation through parliament, the cull is now in the balance.
Food and Fisheries Minister Mogens Jensen apologised for the confusion.
"We should have clearly communicated whether there is legal basis for the authorities to order the killing of healthy mink herds outside the safety zones," he said. "I regret that has not been the case here."
Opposition parties said the cull of healthy mink should not have begun before plans were in place to compensate the owners and workers at around 1,100 mink farms.
“There are huge doubts relating to whether the planned cull was based on an adequate scientific basis. At the same time, one’s depriving a lot of people of their livelihoods,” said Jakob Ellemann-Jensen, leader of the opposition Liberals.
If the government does not receive the 75 per cent backing for its emergency bill, it can use the standard legislation-making route which takes longer but requires 50 per cent support.
Kare Molbak, Denmark's senior epidemiologist, told newspaper Politiken that the arrival of coronavirus was a clear game-changer for mink farming. Maintaining the industry now "represents far too high a national health risk," he said.
Even if the current mutation – cluster 5 – dies out, “there’d be new variants in mink that would spawn equivalent or bigger problems,” Mr Molbak said.
The cull was started after health authorities found virus strains in humans and in mink which showed decreased sensitivity against antibodies.
The UK imposed an emergency ban on flights and ships to England from Denmark to try to stop the spread of the new strain of coronavirus.
British Health Minister Matt Hancock suggested on Tuesday the international community should look again at mink farming, alluding to a potential ban on the industry.
Mr Hancock earlier spoke of grave consequences if the variant became widespread, although he said the chances of that were low.
"There is an international case on public health grounds for addressing this question of mink farming which we banned in the UK two decades ago. It was due to come to an end in Europe in 2023, anyway," he told the UK parliament.
"Clearly on global public health grounds, there is a case to do everything we can to stop the re-transmission of this virus into an animal population and then back again, which can lead to these sorts of mutations that we've seen."
The World Health Organisation (WHO) has called for full-scale scientific investigations into the issue of humans infecting mink, which in turn transmitted the virus back to humans.
Denmark, Italy, the Netherlands, Spain, Sweden and the US have discovered SARS-CoV-2 in mink, the WHO said.